A Reconfigurable Optical Add-Drop Multiplexer (ROADM) is a key technology for automatic scheduling of wavelength-level services in Wavelength Division Multiplexing (WDM) optical networks. Service side ports of an integrated circuit board for ROADMs (also referred to as ROADM card) in different directions inside ROADM nodes are interconnected each other by optical fibers, which physically realizes cross between services in different directions. When the network management layer performs a service scheduling, it is necessary to query the physical connection topology information of the optical fiber on service side ports of ROADMs in different directions to realize a correct scheduling of service routes. For example, interconnections and intercommunications between service sides of the integrated circuit board for ROADMs in four directions inside a 4-dimensional ROADM node needs 6 pairs of optical fiber connections, and interconnections and intercommunications between service sides of the integrated circuit board for ROADMs in eight directions inside a 8-dimensional ROADM node needs 28 pairs of optical fiber connections, further interconnections and intercommunications between the service sides of the integrated circuit board for ROADMs in twenty directions inside a 20-dimensional ROADM node needs 190 pairs of optical fiber connections.
At present, information on actual optical fiber connections among service sides of ROADMs in different directions inside ROADM nodes is usually entered into a database in advance by manual configuration for ROADM to automatically schedule service channels. However, this manner is inefficient, has poor real-time performance, is prone to error, and is difficult to check after an error occurs. In another method, a route matching is realized based on detecting spectrum information output from line sides of ROADM, however, the speed of collecting spectrum information is slow, and the route matching is depending on a service channel being opened in advance and may not be realized before the service channel is opened, further, the configuration of the existing service may not be unaffected; when a network scale is large, wavelengths intersected among different directions may be multiplexed, e.g., there is a wavelength l between direction a and direction b, and there is also a wavelength l between direction c and direction d, so an accurate matching may not be completed only by depending on a service wavelength which does not carry information on a routing direction. There is also a method of using an optical backplane to avoid optical fiber connections on external service sides, however, the reliability is low and the cost is high, and when a ROADM dimension is large, sharing backplane also causes the chassis to be bulky.
On account of this, it is an urgent problem to be solved in the art to overcome above defects existing in the prior art.